A Kaatsu muscle training method capable of efficiently strengthening muscles by restricting a blood flow to apply a load to the muscles has been developed and is used in practice (for example, see Patent Document 1). In such a muscle training method, a muscle strengthening tool is used. The tool includes a tight fitting device with which a certain part of the limbs (arms and legs) of a user is tightened to apply a compression force to muscles. At the present time, a technique of increasing and decreasing the compression force applied to a certain part the limbs of a user is developed. The technique improves the efficiency of the Kaatsu muscle training and also improves the safety of the Kaatsu muscle training (for example, see Patent Document 2).